Medieval Church built between 1100 and the end of the fourteenth century. The themes represented in the facade, on the bas-reliefs and high reliefs, depicting Christ with St. Lowrence and the Tree of Jesse. On either side of the staircase, two lions of the Gothic period (1840), by the sculptor Carlo Rubatto, and other bas-relief lions on the portal by Benedict Antelami school. The interior of the Cathedral has three naves, the central one is covered with marble, divided by columns topped with fake women's gallery and capitals that date from the early fourteenth century. On the middle door, two frescoes painted between the late thirteenth and early fourteenth century depicting the Last Judgment and the Glorification of the Virgin, in Byzantine style, reminiscent of the contemporary patterns in use in Constantinople. The right aisle holds a grenade, miraculously unexploded from the Second World War; along the left nave is the St. John the Baptist's Chapel, built between 1450 and 1465. In the bottom of the right aisle leads to the Museum of the St. Lowrence's Treasure, a masterpiece by Franco Albini, finished in 1956, where it can see objects holy precious, including the so-called Sacred Basin, handmade glass of Islamic art of IX-X century. Many interior decorations are by unknown Byzantine painter, of about 1300: frescoes in the inner bezel of the main portal and over, in addition to those of the left nave (St. Peter and St. George).